1. Field of the Invention
The present invention relates to a network manager, nodes and a network management system, and more particularly to a network manager, nodes and a network management system suitable for realizing highly reliable communications in a large scale network such as telecommunications carrier.
2. Description of the Related Art
The Internet configures a network by using routers. As described, for example, in xe2x80x9cMastering TCP/IPxe2x80x9d an introduction volume, published on Jun. 24, 1994 (Ohm Company), pp. 134-139, a router determines a forward site of a received packet by referring to a destination IP address written in an IP header field of the packet and a routing table of the router, and forwards the packet to the determined forward site.
As described, for example, in xe2x80x9cComputer and Network LANxe2x80x9d, December 1996 (Ohm Company), pp. 2-12, an IP packet transfer method using an asynchronous transfer mode (ATM) is known. With this method, each ATM node monitors a flow of an IP packet, and when an IP packet flow having a speed higher than a predetermined value and the same destination and application is detected, a logical connection is established between adjacent ATM nodes to thereafter transfer the IP packet having the same destination by using the established logical connection.
With a conventional router system, however, if accesses are concentrated upon a server program at a particular Web site, the communication traffics to an application of this Web site hinders other IP traffics.
The above-described conventional ATM method sets a logical connection for each data flow. Therefore, the number of logical connections may become insufficient in a large scale network. In addition, since the logical connection is dynamically set in accordance with judgements by local or adjacent nodes to transfer an IP packet, communication traffics to an application of a particular Web site may hinder other IP traffics, similar to the conventional router system.
It is a first object of the present invention to provide a network manager, nodes and a network management system wherein even if accesses are concentrated upon a particular application, the communication traffics to the application do not hinder other IP traffics irrespective of whether a router system and an ATM method are used.
It is a second object of the present invention to provide a network manager capable of supplying a sufficient number of logical connections in an ATM network.
(1) In order to achieve the first object of the invention, a network manager of this invention for managing relay nodes and edge nodes constituting a communication network, comprises logical connection setting request means for requesting relay nodes and edge nodes to set a logical connection specifying at least one of a source and a destination between an ingress and an egress of the connection.
With this configuration, an access to a particular application is transferred to a logical connection. Therefore, even if accesses are concentrated, the communication traffics to the application do not hinder other IP traffics.
(2) The network manager described in (1) may further comprises distributing means for distributing QoS (Quality of Service) parameter conversion information to the relay nodes and edge nodes, the QoS parameter conversion information being used when node independent QoS parameters are converted into node dependent QoS parameters.
With this configuration, the network manager can set the QoS by designating node independent QoS parameters so that the QoS independent from node types can be guaranteed.
(3) In order to achieve the first embodiment, in a network management system of this invention having relay nodes and edge nodes constituting a communication network and a network manager for managing the relay nodes and edge nodes, the network manager comprises logical connection setting request unit for requesting relay nodes and edge nodes to set a logical connection between an ingress and an egress of the connection; and the relay nodes and the edge nodes each comprise logical connection setting unit responsive to a request by the logical connection setting request unit for setting a logical connection specifying at least one of a transmission source and a destination.
With this configuration, an access to a particular application is transferred to a logical connection. Therefore, even if accesses are concentrated, the communication traffics to the application do not hinder other IP traffics.
(4) In order to achieve the second object, a network manager of this invention for managing relay nodes and edge nodes constituting a communication network comprises logical connection setting request unit for requesting to set a logical connection between an ingress and an egress of the connection, by not limiting a transmission source of the logical connection to be set and by limiting a destination IP address or destination IP address and IP sub-net mask, a destination transport layer protocol type, and a destination application port number.
With this configuration, a logical connection not specifying a transmission source can be set. Since the same logical connection can be used for multiplex communications, the number of logical connections does not become insufficient.